Single-wafer type heat treatment apparatus for semiconductor processing system

ABSTRACT

A single-substrate heat-processing apparatus ( 2 ) for a semiconductor processing system includes a process container ( 4 ) configured to accommodate a target substrate (W). A support member ( 6 ) is disposed in the process container ( 4 ) and configured to support the target substrate (W) substantially in a horizontal state, while a bottom surface of the target substrate is exposed. A heating gas supply section ( 20 ) is disposed to generate a heating gas and supply the heating gas toward the bottom surface of the target substrate (W). A distribution member ( 16 ) is disposed within a flow passage of the heating gas supplied from the heating gas supply section ( 20 ), and configured to improve distribution uniformity of the heating gas onto the bottom surface of the target substrate (W).

TECHNICAL FIELD

The present invention relates to a single-substrate heat-processingapparatus for heat-processing target substrates one by one in asemiconductor processing system. The term “semiconductor process” usedherein includes various kinds of processes which are performed tomanufacture a semiconductor device or a structure having wiring layers,electrodes, and the like to be connected to a semiconductor device, on atarget substrate, such as a semiconductor wafer or a glass substrateused for an LCD (Liquid Crystal Display) or FPD (Flat Panel Display), byforming semiconductor layers, insulating layers, and conductive layersin predetermined patterns on the target substrate.

BACKGROUND ART

In manufacturing semiconductor devices, a circuit pattern is transferredonto a photo-resist, using a photo lithography technique, and thephoto-resist is subjected to a developing process. Where a photolithography technique is used, it is necessary to perform, for example,a hydrophoby-providing step, resist coating step, developing step,baking step, cleaning step, etc.

As a baking step, there is a pre-baking step and a post-baking step. Thepre-baking step is performed to heat and vaporize residual solvent in aresist applied on a semiconductor wafer, thereby baking and curing theresist. The post-baking step is performed to heat and vaporize residualdeveloping solution in the resist after it is developed.

In a semiconductor processing system for performing a photo lithographytechnique, a plurality of process apparatuses for performing respectivesteps are integrated and combined to improve the operating efficiency.Heat-processing means for baking (heating means) is formed of pre-bakingunits and post-baking units stacked one on the other (for example, Jpn.Pat. Appln. KOKAI Publication No. 8-274015). One heat-processing unitmay be commonly used for pre-baking and post-baking.

A heat-processing apparatus of this kind includes a hot plate formed of,e.g., a ceramic plate of SiC or the like with resistance heating wiresbuilt therein. On the hot plate, a semiconductor wafer having a topsurface coated with a resist film is placed. Then, the semiconductorwafer is kept at e.g., about 150° C. for a predetermined time to bakeand cure the resist film.

In order to ensure high accuracy in the thickness of the resist film andplanar uniformity thereof, it is necessary to control temperature inheating the semiconductor wafer and planar uniformity thereof with highaccuracy. For this reason, the hot plate described above is prepared tohave a plurality of, e.g., ten-odd, heating zones planarly arrayed, inwhich thermo couples are respectively disposed. On the basis of thetemperature detected by the thermo couples, heaters are independentlycontrolled for respective heating zones.

However, where the hot plate includes a number of heating zones thusdivided, which are controlled for temperature with high accuracy, a verycomplex structure is required, which increases the cost. Further, thiscomplex structure remarkably increases the weight of the apparatus.

As another heat-processing apparatus, there is one in which a heatinggas flows on the opposite sides of a semiconductor wafer, while thesemiconductor wafer is floated by the gas (for example, Jpn. Pat. Appln.KOKAI Publication No. 2000-091249). However, in this apparatus, theheating gas blown onto a resist film affects the thickness of the resistfilm and planar uniformity of the thickness.

The problems described above are becoming more serious in recent years,as the wafer size increases from 200 mm to 300 mm, line width is furtherminiaturized, and film thickness is reduced.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a heat-processingapparatus, which has a simple structure and can control the temperatureof a target substrate to be planarly uniform with high accuracy.

According to a first aspect of the present invention, there is provideda single-substrate heat-processing apparatus for a semiconductorprocessing system, the apparatus comprising;

-   -   a process container configured to accommodate a target        substrate;    -   a support member configured to support the target substrate        substantially in a horizontal state within the process        container, while a bottom surface of the target substrate is        exposed;    -   a heating gas supply section configured to generate a heating        gas and supply the heating gas toward the bottom surface of the        target substrate; and    -   a distribution member disposed within a flow passage of the        heating gas supplied from the heating gas supply section, and        configured to improve distribution uniformity of the heating gas        onto the bottom surface of the target substrate.

The apparatus according to the first aspect may typically take thefollowing arrangement:

The distribution member is disposed directly below the target substratesupported by the support member, and has a structure in whichventilation directions are substantially random to form a turbulentstate of the heating gas.

The support member comprises a support plate having an opening slightlysmaller than the target substrate, and the target substrate is placed onthe support plate during a heat process such that the bottom surface isexposed from the opening.

The support plate is disposed to divide an interior of the processcontainer into a process chamber on an upper side and a heating chamberon a lower side, and the target substrate is placed on the support plateduring the heat process such that the opening is closed by the targetsubstrate to prevent the heating gas from flowing from the heatingchamber into the process chamber.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a structural view showing a single-substrate heat-processingapparatus for a semiconductor processing system according to a firstembodiment of the present invention;

FIG. 2 is a plan view showing a support member used in the apparatusshown in FIG. 1;

FIG. 3 is a plan view showing a gas spouting pipe having a ring shapeused in a modification of the apparatus shown in FIG. 1;

FIG. 4 is a structural view showing a single-substrate heat-processingapparatus for a semiconductor processing system according to a secondembodiment of the present invention;

FIG. 5 is a plan view showing a resistance heating wire used in theapparatus shown in FIG. 4; and

FIG. 6 is a structural view showing a single-substrate heat-processingapparatus for a semiconductor processing system according to a thirdembodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will now be described withreference to the accompanying drawings. In the following description,the constituent elements having substantially the same function andarrangement are denoted by the same reference numerals, and a repetitivedescription will be made only when necessary.

First Embodiment

FIG. 1 is a structural view showing a single-substrate heat-processingapparatus for a semiconductor processing system according to a firstembodiment of the present invention. FIG. 2 is a plan view showing asupport member used in the apparatus shown in FIG. 1. This apparatus isarranged to bake a photo-resist film applied on the top surface of atarget substrate or semiconductor wafer.

As shown in FIG. 1, the heat-processing apparatus 2 has a processcontainer 4 with a rectangular cross section, which is made of, e.g.,aluminum and sized to accommodate a semiconductor wafer W. The interiorof the process container 4 is divided into a process chamber S on theupper side and a heating chamber H on the lower side, by a support plate8 used as a support member 6 for supporting the wafer W in a horizontalstate. A door 12 is disposed on the sidewall of the process container 4at a position corresponding to the process chamber S, and is configuredto be opened and closed by, e.g., movement up and down, for transfer ofthe wafer W.

The support plate 8 is made of a heat resistant ceramic, such asalumina. The support plate 8 has an essentially circular opening 10 atthe center. The opening 10 has a size almost the same as or larger thana region of the wafer W in which an array of semiconductor devices is tobe formed. More specifically, where the wafer W has a diameter of 300mm, the opening 10 has a diameter slightly smaller than this, e.g.,smaller by about 6 mm.

When the wafer W is supported in a horizontal state at a normal positionon the support plate 8, the wafer W is concentric with the opening 10,and the bottom surface of the wafer W is exposed from the opening 10.Further, in this state, the opening 10 is entirely closed by the waferW, so the process chamber S and heating chamber H are separated on theupper and lower sides in the process container 4. The bottom surface ofthe rim portion of the wafer W is in face-contact with the top surfaceof the edge portion 8A all around, to prevent gas from diffusing betweenthe heating chamber H on the lower side and the process chamber S on theupper side.

A distribution member 16 is disposed within the heating chamber H toimprove distribution uniformity of a heating gas onto the bottom surfaceof the wafer W. The distribution member 16 is formed of a heat resistantporous plate 18, which is flat and faces the wafer W in paralleltherewith immediately below the support plate 8 (and immediately belowthe wafer W). The porous plate 18 stretches all over a horizontal planewithin the heating chamber H to further partition the interior of theheating chamber H into two spaces on the upper and lower sides.Accordingly, the porous plate 18 covers the entire bottom surface of thewafer W exposed from the opening 10 of the support plate 8.

The porous plate 18 has a thickness of, e.g., about 5 mm and a vacancyrate set such that the porous plate 18 does not generate a largepressure difference in the heating gas. The porous plate 18 has astructure in which ventilation directions are set substantiallyrandomly. Accordingly, when the heating gas passes through the porousplate 18, the gas is dispersed in horizontal directions and changed intoa turbulent state, and then comes into contact with the bottom surfaceof the wafer W in this state. As a consequence, the heating gas canuniformly come into contact with the bottom surface of the wafer W,which improves the planar uniformity of the wafer temperature.

The heat resistant porous plate 18 with random ventilation directionsmay be a plate made essentially of a material selected from the groupconsisting of a foamed ceramic, such as foamed quartz, and a poroussintered ceramic, such as porous SiC. In place of such a porous plate,the distribution member 16 may be formed of a punched metal having anumber of through holes, or a fin combination in which a number oftwisted short fins are planarly arrayed.

The process container 4 is connected to a heating gas supply section 20,which generates a heating gas and supplies it to the bottom surface ofthe wafer W. More specifically, a gas feed port 24 is formed in thesidewall of the heating chamber H and below the porous plate 18. The gasfeed port 24 is connected to a heating box 30 with a heater 26 builttherein, and a blower 28, through a gas feed passage 22. The heating gasmay be an inactive gas, such as N₂ gas, or clean air.

The heater 26 is formed of a resistance heating wire 26A, such as acarbon wire, which heats a gas in contact therewith to generate theheating gas. Alternatively, for example, an arrangement may be adoptedsuch that fillers are disposed in a heat resistant heating box 30, and aresistance heating wire 26A is disposed around the heating box 30, sothat a gas flowing through the fillers is heated. This can generate aheating gas with less metal contamination.

The blower 28 is formed of, e.g., a blower fan, and sends a gas to theheating box 30, which heats the gas, and then to the heating chamber H.Where the gas is N₂ gas and flows under the pressure of a gas source,the blower 28 may be omitted. The downstream side of the gas feedpassage 22 is provided with a flow control valve 32, which adjusts theflow passage area to control the flow rate of the heating gas.

An elevating member 34 is disposed below the wafer W to support thebottom surface of the wafer W and move the wafer W up and down. Morespecifically, the elevating member 34 has a plurality of, e.g., three,lifter pins 36 (FIG. 1 shows only two of them), which penetrate thedistribution member 16 and are movable up and down through the opening10. The bottoms of the lifter pins 36 are connected to, e.g., a lifterring 38. The lifter ring 38 is connected to an actuator rod 40, whichpenetrates the bottom of the process container 4 and is connected to adriving source (not shown). The lifter pins 36 are moved up and down bythe actuator rod 40 moving up and down, while the lifter pins 36 supportthe bottom surface of the wafer W at the top, so as to assist transferof the wafer.

Since the interior of the process container 4 needs not be highlyairtight, no bellows is required at the portion where the actuator rod40 penetrates. The actuator rod 40 may be extended in a horizontaldirection, and connected to a driving source (not shown) disposedoutside the sidewall of the process container 4. This modification isadvantageous where a plurality of heat-processing apparatuses arestacked, because their actuator rods 40 do not interfere with eachother.

A plurality of gas ports 42 are formed, e.g., four ports areequidistantly formed in this example (see FIG. 2), in the sidewall ofthe heating chamber H and above the porous plate 18. The gas ports 42are connected through gas lines 43 to an exhaust section 46, whichexhausts the heating gas after it heats the wafer W. The gas lines 43are also connected to a cooling gas supply section 47, which supplies acooling gas for cooling the heated wafer W. Switching valves 46 a and 47a are provided for the exhaust section 46 and cooling gas supply section47, respectively, and are operated in accordance with a program forbaking a photo-resist film, which is stored in the CPU of theheat-processing apparatus 2.

The number of gas ports 42 is not limited to four, and the processcontainer 4 may be provided with two, three, five, or more gas portsdisposed at, e.g., regular internals in an angular direction. In anycase, they are preferably arranged to uniformly exhaust a heating gas,and to feed a cooling gas. The cooling gas may be clean air takentherein at an ambient room temperature, or clean air or an inactive gascooled in advance.

An exhaust port 44 is formed in the sidewall of the heating chamber Hand below the porous plate 18, to exhaust the cooling gas. The exhaustport 44 is connected through an exhaust line 45 to an exhaust section48, which exhausts the cooling gas after it cools the wafer W. Aswitching valve 48 a is provided for the exhaust section 48, and isoperated in accordance with a program stored in the CPU (it is closedwhen the wafer W is heated). The exhaust sections 46 and 48 areconnected to a factory exhaust duct or the like.

It should be noted that the term “exhaust section” used in thisspecification includes not only a member having a forcible exhaustfunction, such as a pump or fan, but also a simpler member, such aspiping for exhaust gas connected to a factory exhaust duct.

A gas feed port 50 for supplying a gas and an exhaust port 52 forexhausting the gas are formed in the sidewall of the process chamber S.The gas feed port 50 is connected to a gas supply section 57 through aline 56 provided with a flow regulator 54, such as a mass-flowcontroller. An inactive gas, such as N₂ gas, or clean air is suppliedfrom the gas supply section 57 into the process chamber S at acontrolled flow rate. It may be arranged to directly supply ambientclean gas through the gas feed port 50.

The exhaust port 52 is connected to, e.g., a factory exhaust duct, sothat the atmosphere inside the process chamber S is naturally exhausted.An exhaust fan may be disposed at the exhaust port 52 to performforcible exhaust.

A temperature detector 58, such as a thermo couple, is disposed directlybelow the semiconductor wafer W, to detect the temperature of theheating gas, which has passed through the porous plate 18 and flowsupward in a turbulent state. Based on the value detected by thetemperature detector 58, a heating gas control section 60 formed of,e.g., a micro-computer adjusts the electrical power applied to theresistance heating wire 26A, thereby controlling the temperature of theheating gas. The heating gas control section 60 operates in cooperationwith the CPU of the heat-processing apparatus 2.

Next, an explanation will be given of an operation of theheat-processing apparatus 2 according to the first embodiment describedabove. The operation described below is performed in accordance with aprogram for baking a photo-resist film, which is stored in the CPU ofthe heat-processing apparatus 2.

First, a semiconductor wafer W with a photo-resist film applied on thesurface is transferred by the transfer arm (not shown) into the processchamber S of the process container 4 through the opened door 12. Then,the lifter pins 36 are moved up to receive the wafer W by them.Thereafter, the transfer arm is retreated, and the lifter pins 36 aremoved down to place the wafer W on the support plate 8, as shown in FIG.1.

As shown in FIG. 1, when the wafer W is supported in a horizontal stateat the normal position on the support plate 8, the wafer W is concentricwith the opening 10, and the bottom surface of the wafer W is exposedfrom the opening 10. Further, in this state, the opening 10 is entirelyclosed by the wafer W, so the process chamber S and heating chamber Hare separated on the upper and lower sides in the process container 4.The bottom surface of the rim portion of the wafer W is in face-contactwith the top surface of the edge portion 8A all around, to prevent gasfrom diffusing between the heating chamber H on the lower side and theprocess chamber S on the upper side.

Then, the blower 28 of the heating gas supply section 20 is activated tosupply a gas G1, such as clean air, or an inactive gas, e.g., N₂ gas.The gas G1 is heated by the resistance heating wire 26A of the heater 26within the heating box 30, up to a predetermined temperature, and issupplied as a heating gas G2 to the bottom side within the heatingchamber H through the gas feed port 24. The heating gas G2 flows upwardwhile diffusing within the heating chamber H, and passes through theporous plate 18 of the distribution member 16 with high permeability,and then comes into contact with the bottom surface of the wafer W toheat up the wafer W.

Since the ventilation directions of the porous plate 18 are set in alldirections, the heating gas is changed into a turbulent state whenpassing through the porous plate 18, and then comes into contact withthe bottom surface of the wafer W in this state. As a consequence, thewafer W is heated to a temperature with high planar uniformity.

At this time, the opening 10 of the support plate 8 is entirely closedby the wafer W, so the process chamber S and heating chamber H areseparated on the upper and lower sides in the process container 4. Theheating gas is thus prevented from diffusing from the heating chamber Hinto the process chamber S, so that the heating gas cannot come intodirect contact with the photo-resist film applied onto the top surfaceof the wafer W. As a consequence, the photo-resist film is not affectedby the heating gas.

After coming into direct contact with the bottom surface of the wafer W,the heating gas is exhausted as an exhaust gas G3 through the gas ports42 formed in the sidewall of the heating chamber H. The exhaust gas G3flows through the line 43 and exhaust section 46, and is eventuallydischarged outside through a factory exhaust duct or the like. At thistime, the switching valve 46 a for the exhaust section 46 is opened,while the switching valves 47 a and 48 a for the cooling gas are closed.Since a plurality of gas ports 42 are formed along the periphery of theprocess container 4, the heating gas is exhausted without large drifts.

As a consequence, the wafer is prevented from been affected in terms ofthe planar uniformity of temperature.

The temperature of the wafer W in baking is set to be within a range of,e.g., from 90 to 250° C. The temperature of the heating gas havingpassed through the porous plate 18 is detected by the thermo couple ortemperature detector 58. Based on the detected value, the heating gascontrol section 60 controls the electrical power applied to theresistance heating wire 26A. As a consequence, the temperature of theheating gas is maintained at a predetermined constant temperature withina range of from 90 to 250° C., e.g., 150° C.

The wafer W is subjected to the heat process (baking) described abovefor a predetermined time, e.g., about 90 seconds, and the photo-resistfilm is thereby baked and cured. During this heat process, a gas, suchas an inactive gas, e.g., N₂ gas, or clean air, is supplied into theprocess chamber S on the upper side of the wafer W. This gas isexhausted, along with a solvent gas generated from the photo-resistfilm, through the exhaust port 52 into a factory exhaust duct, bynatural exhaust or forcible exhaust using a fan.

The flow rate of the gas supplied into the process chamber S iscontrolled by the flow regulator 54, so that the atmosphere inside theprocess chamber S is kept at essentially constant values of temperatureand humidity. At this time, the interior of the process chamber S is setat a pressure slightly positive by, e.g., about 50 Pa, relative to theheating chamber H on the lower side. As a consequence, the heating gasis reliably prevented from flowing into the process chamber S.

After the heat process described above for baking and curing thephoto-resist film is finished, a cooling step starts. In this step, atfirst, the electric power supply to the resistance heating wire 20A isstopped, and the flow control valve 32 within the gas feed passage 22 isclosed, to stop supply of the heating gas G2. At the same time, theswitching valve 46 a for the exhaust section 46 is closed, while theswitching valves 47 a and 48 a for the cooling gas are opened.

With this change, the cooling gas C1 starts being supplied through thegas ports 42, through which the heating gas was exhausted until now. Thecooling gas C1 flows into the heating chamber H below the bottom surfaceof the wafer W, and cools the wafer W from the bottom. The cooling gasthus used passes through the porous plate 18 downward to the exhaustport 44. Then, the cooling gas used flows through the line 45 andexhaust section 48, and is eventually discharged outside through afactory exhaust duct or the like.

The cooling gas may be exhausted through the line 45, not byvacuum-exhaust using the exhaust section 48, but by natural exhaustusing a factory exhaust duct. An exhaust fan may be disposed at theexhaust port 44 to perform forcible exhaust. The cooling gas suppliedthrough the gas ports 42 may be clean air at an ambient roomtemperature, or a cooling gas actively cooled to a low temperature.

According to the first embodiment, the wafer W can be subjected to aheat process while being set at a temperature with high planaruniformity, without a complicated heating control using a plurality ofheating zones, as described in the conventional heat-processingapparatus. Since the heating gas supply section for generating theheating gas has a simple structure, the entire arrangement of theapparatus can be simplified, thereby reducing the cost that much.

Further, the top surface of the wafer W is not exposed to the heatinggas flowing or blowing thereon. As a consequence, the photo-resist film,which can be easily affected by, e.g., external factors, is baked andcured without receiving ill effects, so that the photo-resist film canhave an improved uniformity of the thickness.

In the structure shown in FIG. 1, the gas feed port 24 is formed in alower portion of the sidewall of the process container 4. Alternatively,a gas feed port 24 may be disposed near the center of the bottom of theprocess container 4 to promote distribution of the heating gas.

In place of the gas feed port 24, a gas spouting pipe having a ringshape connected to the gas feed passage 22 may be used. FIG. 3 is a planview showing a gas spouting pipe having a ring shape used in amodification of the apparatus shown in FIG. 1. In the modification shownin FIG. 3, a gas spouting pipe 62 having a ring shape connected to thegas feed passage 22 is disposed on the bottom of the heating chamber H.The gas spouting pipe 62 is provided with a number of gas spouting holes62A formed thereon, from which the heating gas is spouted. Themodification shown in FIG. 3 can further promote distribution of theheating gas.

Second Embodiment

FIG. 4 is a structural view showing a single-substrate heat-processingapparatus for a semiconductor processing system according to a secondembodiment of the present invention. FIG. 5 is a plan view showing aresistance heating wire used in the apparatus shown in FIG. 4. In thefirst embodiment shown in FIG. 1, the heater 26 of the heating gassupply section 20 is disposed outside the process container 4 and on themiddle of the gas feed line 22. The heater 26, however, may be disposedwithin the process container 4. The apparatus according to the secondembodiment is arranged on the basis of this idea.

As shown in FIG. 4, the apparatus according to the second embodimentincludes a heater 26 with a resistance heating wire 26A horizontallydisposed directly below a porous plate 18. As shown in FIG. 5, theresistance heating wire 26A is planarly extended, e.g., in a meanderingstate, to cover substantially the entire bottom surface of the wafer Wexposed from the opening 10 of the support plate 8.

Further, an auxiliary distribution member 64 is disposed directly belowthe resistance heating wire 26A, to improve distribution uniformity of asupplied gas. The auxiliary distribution member 64 is formed of, e.g., apunched metal with a plurality of through holes 64A uniformlydistributed in a plane. A gas G1 to be heated is take into from a gasfeed port 24, and is essentially uniformly distributed by the auxiliarydistribution member 64, when it flows to the resistance heating wire26A.

The auxiliary distribution member 64 is not limited to a punched metal,and it may be a member similar to the porous plate 18 disposedthereabove, e.g., a foamed quartz plate with a small thickness and highpermeability. It should be noted that any of the modifications describedin relation to the first embodiment can be applied to the secondembodiment.

The second embodiment provides the same operations and effects as thoseof the first embodiment. Specifically, for example, the wafer W can besubjected to a heat process while being set at a temperature with highplanar uniformity, without a complicated heating control using aplurality of heating zones, as described in the conventionalheat-processing apparatus. Since the heating gas supply section forgenerating the heating gas has a simple structure, the entirearrangement of the apparatus can be simplified, thereby reducing thecost that much.

Further, the top surface of the wafer W is not exposed to the heatinggas flowing or blowing thereon. As a consequence, the photo-resist film,which can be easily affected by, e.g., external factors, is baked andcured without receiving ill effects, so that the photo-resist film canhave an improved uniformity of the thickness.

According to the second embodiment, since the heater 26 is disposedwithin the process container 4, heating becomes more efficient. Further,the auxiliary distribution member 64 is disposed directly below theresistance heating wire 26A of the heater 26. This promotes distributionof the supplied gas G1, thereby further improving planar uniformity ofthe wafer temperature. Incidentally, the auxiliary distribution member64 may be disposed in the heat-processing apparatus according to thefirst embodiment. In addition, when the wafer W is cooled, residual heatof the resistance heating wire 26A is discharged downward by the coolinggas. As a consequence, the residual heat of the resistance heating wire26A is prevented from affecting the efficiency of cooling the wafer W.

In FIG. 4, the gas feed port 24 and exhaust port 44 are respectivelyformed in the sidewall of the process container 4 below the porous plate18. However, an arrangement may be adopted such that only one of theseports, e.g., gas feed port 24, is formed, and the exhaust line 45 isbranched from the gas feed line 22 connected to the port 24. Thisstructural modification may be also applied to the first embodimentshown in FIG. 1.

Third Embodiment

FIG. 6 is a structural view showing a single-substrate heat-processingapparatus for a semiconductor processing system according to a thirdembodiment of the present invention. In the first and second embodimentsshown in FIGS. 1 and 4, after coming into contact with the bottomsurface of the wafer W, the heating gas flows horizontally outward inthe radial direction of the wafer W, and is exhausted directly out ofthe process container 4 through the gas ports 42 formed in the sidewallof the container. However, an arrangement may be adopted such that,after coming into contact with the bottom surface of the wafer W, theheating gas turns round downward and is exhausted. The apparatusaccording to the third embodiment is arranged on the basis of this idea.

As shown in FIG. 6, the apparatus according to the third embodimentincludes a plurality of exhaust pipes 70 disposed at intervals in thehorizontal plane of a flat porous plate 18 constituting a distributionmember 16. Each of the exhaust pipes 70 is formed of, e.g., an aluminumpipe having an inner diameter of about 10 mm, which perpendicularlypenetrates the horizontal porous plate 18. The bottoms of the exhaustpipes 70 are connected to a gas collecting head 72, which is formed of ahollow circular plate made of, e.g., aluminum, and disposed within alower portion of the process container 4. The gas collecting head 72 isconnected on one side to an exhaust line 45 penetrating the sidewall ofthe container. In order not to interfere with the heating gas flowingupward within the heating chamber H, the gas collecting head 72 ispreferably set to have a relatively small diameter.

According to the third embodiment, the heating gas G2 supplied into theheating chamber H is changed into a turbulent state when passing throughthe porous plate 18 upward, and then comes into contact with the bottomsurface of the wafer W. Thereafter, the heating gas turns round downwardand flows as a backward heating gas G4 down through the exhaust pipes 70nearby and into the gas collecting head 72. The gas collected in the gascollecting head 72 is discharged outside through the exhaust line 45.While the wafer is subjected to the heat process, the gas ports 42 arekept closed, so that no heating gas flows out through the gas ports 42.

After the heat process, the gas ports 42 are opened to supply thecooling gas therethrough when a cooling step is performed. The coolinggas flows onto the bottom surface of the wafer W to cool the wafer W,and is then discharged outside through the exhaust pipes 70, gascollecting head 72, and line 45, as in the heating gas. It should benoted that any of the modifications described in relation to the firstand second embodiments can be applied to the third embodiment.

The third embodiment provides the same operations and effects as thoseof the first embodiment. Specifically, for example, the wafer W can besubjected to a heat process while being set at a temperature with highplanar uniformity, without a complicated heating control using aplurality of heating zones, as described in the conventionalheat-processing apparatus. Since the heating gas supply section forgenerating the heating gas has a simple structure, the entirearrangement of the apparatus can be simplified, thereby reducing thecost that much.

Further, the top surface of the wafer W is not exposed to the heatinggas flowing or blowing thereon. As a consequence, the photo-resist film,which can be easily affected by, e.g., external factors, is baked andcured without receiving ill effects, so that the photo-resist film canhave an improved uniformity of the thickness.

According to the third embodiment, the heating gas comes into contactwith the bottom surface of the wafer W, and is then exhausted through anumber of exhaust pipes 70 distributed in the porous plate 18 and thegas collecting head 72. As a consequence, the heating gas is exhausteduniformly in the horizontal direction below the wafer W, which furtherimproves the planar uniformity of the wafer temperature.

The first to third embodiments are exemplified by a case where a heatprocess is used for a photo-resist film applied on the top surface of awafer W to be baked and cured by the heat process (baking). The presentinvention may be applied to another heat process. The target substrateis not limited to a semiconductor wafer, and the present invention maybe applied to a glass substrate for an LCD or FPD, or another materialsubstrate.

INDUSTRIAL APPLICABILITY

According to the present invention, there is provided a heat-processingapparatus, which has a simple structure and can control the temperatureof a target substrate to be planarly uniform with high accuracy.

1. A single-substrate heat-processing apparatus for a semiconductorprocessing system, the apparatus comprising; a process containerconfigured to accommodate a target substrate; a support memberconfigured to support the target substrate substantially in a horizontalstate within the process container, while a bottom surface of the targetsubstrate is exposed; a heating gas supply section configured togenerate a heating gas and supply the heating gas toward the bottomsurface of the target substrate; and a distribution member disposedwithin a flow passage of the heating gas supplied from the heating gassupply section, and configured to improve distribution uniformity of theheating gas onto the bottom surface of the target substrate, wherein thedistribution member is disposed directly below the target substratesupported by the support member, and has a structure in whichventilation directions are substantially random to form a turbulentstate of the heating gas.
 2. (canceled)
 3. The heat-processing apparatusaccording to claim 1, wherein the distribution member comprises a heatresistant porous plate consisting essentially of a material selectedfrom the group consisting of foamed ceramics and porous sinteredceramics.
 4. The heat-processing apparatus according to claim 3, whereinthe porous plate consists essentially of foamed quartz.
 5. Theheat-processing apparatus according to claim 1, wherein the supportmember comprises a support plate having an opening slightly smaller thanthe target substrate, and the target substrate is placed on the supportplate during a heat process such that the bottom surface is exposed fromthe opening.
 6. The heat-processing apparatus according to claim 5,wherein the support plate is disposed to divide an interior of theprocess container into a process chamber on an upper side and a heatingchamber on a lower side, and the target substrate is placed on thesupport plate during the heat process such that the opening is closed bythe target substrate to prevent the heating gas from flowing from theheating chamber into the process chamber.
 7. The heat-processingapparatus according to claim 6, further comprising an exhaust passagefor exhausting the heating gas from the heating chamber.
 8. Theheat-processing apparatus according to claim 7, wherein the exhaustpassage comprises a plurality of exhaust pipes disposed at intervals ina horizontal plane and penetrate the distribution member.
 9. Theheat-processing apparatus according to claim 7, further comprising a gassupply section configured to supply a gas into the process chamber, andthe process chamber is set to have a positive pressure relative to theheating chamber during the heat process.
 10. The heat-processingapparatus according to claim 6, further comprising an elevating memberconfigured to support and move the target substrate up and down from thebottom surface, the elevating member being movable up and down throughthe opening.
 11. The heat-processing apparatus according to claim 1,wherein the heating gas supply section comprises a heater configured toheat a gas to generate the heating gas, and a blower configured to sendthe gas to the heater.
 12. The heat-processing apparatus according toclaim 11, wherein the heater is disposed directly below the distributionmember.
 13. The heat-processing apparatus according to claim 11, whereinthe heater comprises a heating portion covering substantially all overthe exposed bottom surface of the target substrate.
 14. Theheat-processing apparatus according to claim 13, further comprising anauxiliary distribution member disposed between the blower and theheater, and configured to improve distribution uniformity of the gassupplied from the blower onto the heater.
 15. The heat-processingapparatus according to claim 1, further comprising a temperaturedetector configured to detect temperature of the heating gas near thebottom surface of the target substrate, and a heating gas controlsection configured to control the heating gas supply section inaccordance with a detected value obtained by the temperature detector.16. The heat-processing apparatus according to claim 1, furthercomprising a cooling gas supply section configured to supply a coolinggas onto the bottom surface of the target substrate, and a processcontrol section configured to selectively supply the heating gas and thecooling gas.
 17. The heat-processing apparatus according to claim 16,wherein the process control section is set to perform baking on aphoto-resist film applied on a top surface of the target substrate. 18.A single-substrate heat-processing apparatus for a semiconductorprocessing system, the apparatus comprising; a process containerconfigured to accommodate a target substrate; a support memberconfigured to support the target substrate substantially in a horizontalstate within the process container, while a bottom surface of the targetsubstrate is exposed; a heating gas supply section configured togenerate a heating gas and supply the heating gas toward the bottomsurface of the target substrate; and a distribution member disposedwithin a flow passage of the heating gas supplied from the heating gassupply section, and configured to improve distribution uniformity of theheating gas onto the bottom surface of the target substrate, wherein thesupport member comprises a support plate having an opening slightlysmaller than the target substrate, and the target substrate is placed onthe support plate during a heat process such that the bottom surface isexposed from the opening, wherein the support plate is disposed todivide an interior of the process container into a process chamber on anupper side and a heating chamber on a lower side, and the targetsubstrate is placed on the support plate during the heat process suchthat the opening is closed by the target substrate to prevent theheating gas from flowing from the heating chamber into the processchamber, and wherein the apparatus further comprises an exhaust passagefor exhausting the heating gas from the heating chamber, and the exhaustpassage comprises a plurality of exhaust pipes disposed at intervals ina horizontal plane and penetrate the distribution member.
 19. Theheat-processing apparatus according to claim 18, wherein thedistribution member is disposed directly below the target substratesupported by the support member, and has a structure in whichventilation directions are substantially random to form a turbulentstate of the heating gas.
 20. The heat-processing apparatus according toclaim 19, wherein the distribution member comprises a heat resistantporous plate consisting essentially of a material selected from thegroup consisting of foamed ceramics and porous sintered ceramics. 21.The heat-processing apparatus according to claim 20, wherein the porousplate consists essentially of foamed quartz.
 22. The heat-processingapparatus according to claim 18, further comprising a gas supply sectionconfigured to supply a gas into the process chamber, and the processchamber is set to have a positive pressure relative to the heatingchamber during the heat process.
 23. The heat-processing apparatusaccording to claim 18, comprising a process control section set toperform baking on a photo-resist film applied on a top surface of thetarget substrate.